JPI Install

[md11flyer]

Hello:
Installing JPI monitors in Pa-30. I have an original CHT probe in the number 3 cylinder and would like to install the jpi number 3 cylinder to this location.
Can you use a JPI adapter probe (m 5050A) in that position for the JPI monitor and change out the old style, AC (spark plug type) factory temp sensor and replace it with a bayonette style probe?
If this is possible, will a jpi bayonette work with the factory guages?
Or am I stuck with having to use a spark plug gasket style CHT probe?

Thanks,
Gary

[MULEFLY]

Gary, I don't have the specific part numbers in front of me... but I do recall that Pat Keefer referenced them in her Flyer article about her panel installation that is available on this web site. I have the two connectors workingin a piggy back mounting. Again, Pat's article has the correct numbers. Mine do not work as well as Pat's... my legally required gages show very little temp movement. Pat flew to Air Parts of Lock Haven and they "tuned" her's in.

I'd love to trash the factory gages and install the JPI primary replacement unit 960... isn't going to happen this year.

All the best!
Jim

[Zach Grant L1011jock]

Gary,
JPI has a ring thermocouple that fits as a gasket under the factory CHT probe. It is better than the spark plug ring by far, and is better than the piggy back fitting that they have also IMHO. I switched to this and have had good results. #3 is always a bit cooler than the others, but I juat add 30 degrees and it seems to work out pretty well. Unfortunately, the only STC available for repairing the factory gauges is the Airparts of Lockhaven STC, and the JPI 760 is not certified as a replacement for any required instrumentation, so you have to keep the factory CHT and Fuel Flow gauges in the panel.
-Zach

[N3322G]

Hi Gary,

Ditto what Zach said.

We did this in 2005 and JPI did have two different ways to handle this problem. I recall talking to them and they advised me on the one that gave the best results. The temp difference is like Zach's about 30 degrees.

On the tuning done by Air Parts of Lock Haven - they rescued me on the CHT probes problem because the shop that installed the JPI pulled and kept the origianl CHT probes without telling me. This shop is no longer in business. I had to get new probes and have them calibrated with the factory gauges. Air Parts' work was excellent and Jim, who worked on the original factory line for Piper still works there and worked on the twin. Good guy.

Hope this helps.

[md11flyer]

Thanks for the replies:

Zach, you mentioned the piggyback probe will work with the original factory probe?
I have the piggy back probes in hand, but after looking at the original probe, I wondered if it would not fit deep enough into the cylinder.
The jpi adapter probe is the 5050A. If this will work with the factory probe then Bob's my uncle and I won't need to order 2 more gasket probes.


Gary

[Zach Grant L1011jock]

Gary,
It should work just fine. As long as you can get enough threads of the factory probe into the boss to hold the ring, it will work fine. With the JPI, really, do you care what the old factory gauge reads? All it has to do is be hooked up and move relative to something to be legal. Like I said, there is a slightly cooler reading from the piggyback probe, due to surface mounting vs being installed in the boss, but it is not terribly significant. If none of this makes sense, then I may be misunderstanding your difficulty. Hope this helps.
-Zach

[md11flyer]

Zach:
Thanks for the quick reply.
Yes, that was my question, I want to just install the old factory probe into the boss of the JPI adapter probe.
The temp of the adapter probe should be close to accurate as the sensor part is in the lower portion of the screw in part.
My guess is that the factory guage will read somewhat lower because its probe sits about 3/8 inch further out of the cylinder boss. (the height of
the adapter probe when fully screwed into the boss).

My only concern is the legalities of a low reading factory guage.... but then again who will know and who will care...when you have a JPI indicator with
the alarms and accurate cht on all 4 cylinders..

Thanks again for your help.

Gary